Comparative Study of Alternative Photochemical Models in Ozone and PM Predictions and their Applications to Population Exposure Assessment
Q. Sun, N. Lahoti, S.W. Wang, and P.G. Georgopoulos
Environmental and Occupational Health Sciences Institute, UMDNJ - R.W. Johnson Medical School and Rutgers University
Photochemical models are instrumental in designing emission control strategies for attaining compliance with air quality standards for pollutants like ozone and fine PM. Due to the complex nature of the problem, different photochemical models may employ substantially different sets of assumptions about the physical and chemical processes involved, and thus produce accordingly different predictions of ambient pollutant concentrations.
Furthermore, successful emission reduction strategies must reduce the number of people potentially exposed to contaminants. Therefore, it is necessary to evaluate not only the predictions of ambient pollutant concentrations by different photochemical models, but also the impact of different predictions on corresponding potential population exposure estimates.
This study used three grid-based photochemical models that have linked to the Modeling ENvironment for TOtal Risk studies (MENTOR) system: US EPA's Community Multiscale Air Quality (CMAQ) model, a component of the Models-3 system, the Regional Modeling System for Aerosols and Deposition (REMSAD), and CAMX, developed by Environ. Simulations were carried out for episodes in 1999 and 2001. The Sparse Matrix Kernel Estimator (SMOKE) was used to process emissions, and the Meteorological Model 5 (MM5) was used to develop meteorological inputs. The ozone and PM predictions from these different models were evaluated using monitor data, and metrics of potential population derived from the different modeling applications were compared.
This work had been funded in part by the US Environmental Protection Agency under Cooperative Agreement # EPAR-827033 to the Environmental and Occupational Health Sciences Institute (EOHSI). The viewpoints expressed here are the responsibility of the authors and do not necessarily reflect the views of the USEPA or its contractors.